PG 1159-035: a New, Hot, Non-Da Pulsating Degenerate (original) (raw)

NASA/ADS

;

• Starrfield, S. G. ;
• Liebert, J. ;
• Green, R.

Abstract

The identification of the blue star PG 1159-035 as a hot, non-DA pulsating degenerate is reported. PG 1159-035 was observed by a high-speed photometer on the Multiple Mirror Telescope to obtain light curves with nearly sinusoidal variations and a peak-to-peak amplitude of about 0.02 magnitude. Power spectra of the light curves exhibit two significant peaks at frequencies of about 1.86 and 2.17 mHz, corresponding to periods of about 539 and 460 sec, respectively. Stromgren photometry indicates an effective temperature greater than 50,000 K, and an energy distribution characteristic of a Rayleigh-Jeans slope has been detected to a wavelength of 3200 A. The data thus indicate that the star is very hot, with a log of surface gravity less than about 8 and a probable depletion in surface hydrogen. The presence of two closely spaced periods in the light curve suggests that the object is a pulsating star rather than a binary, and further evidence indicates that PG 1159-035 is likely to be changing rapidly, possibly becoming a white dwarf.

Publication:

IAU Colloq. 53: White Dwarfs and Variable Degenerate Stars

Pub Date:

1979

Bibcode:

1979wdvd.coll..377M

Keywords:

• Hot Stars;
• Pulsars;
• Stellar Spectra;
• White Dwarf Stars;
• Light Curve;
• Stellar Spectrophotometry;
• Astrophysics